Adapted from W. R. Burnett's novel, a gambler marries; but his wife objects to his betting.
Jim "Buck" Turner (Edward G. Robinson) wins $20,000 on a horse race and quickly loses it. Jim rents a room from Marge Mayhew (Genevieve Tobin) in a boardinghouse over the objections of her mother (Emma Dunn). Marge tells her mother she is going to marry Jim. He works as a hotel night-clerk. Joe (Gordon Westcott) tells John Bright (Sidney Toler) that Jim's tip paid off and gives Jim $60. Bright quarrels with Jim and gets him fired. Jim won't let Marge take a job. Jim finds Bright and hits him and another man; but then Bright befriends Jim and hires him to check out a dog track for $100 a week. They gamble, and Jim wins $6,000, splitting it with Bright. Jim is evicted and tells Marge about his new job.
Jim waters his yard and smooches with Marge. At the dog track Jim reports to George Porter. Jim gets a tip on Dark Hazard but bets on #2. Dark Hazard beats #2. Jim learns that his friend Valerie Wilson (Glenda Farrell) owns #2, and he says he is married. Jim lies to Marge about betting. Porter persuades Jim to bet on #7, but Dark Hazard wins again. Jim meets Dark Hazard's owner Tex Willis (Robert Barrat), and he takes Marge to meet the dog. Jim leaves Valerie to go home late for dinner, and Marge says his rent check bounced. Marge says she is going to have a baby. Valerie and two men call on Jim, but Marge gets them to leave and tells Jim to go. Jim with Valerie gambles $20 and wins $20,000. Jim kisses Valerie but goes home to Marge.
Jim wakes to find that Marge left with all the money except $500 to go home. Jim gambles and loses. He rides a freight train home to Marge. He learns he has a son; but Marge says she is divorcing him, because she wants to marry Pres Barrow (George Meeker). After going out with Pres, Marge comes in and tells Jim she is not getting divorced, and Pres will give Jim a job. Jim works as a cashier for Pres. George Mayhew (Hobart Cavanaugh) tells Jim of a new dog track. Jim sees Tex, and Dark Hazard hurts his leg. Jim buys the dog for $25 and takes care of him. Jim drinks with George and says he is going to take Marge away. Jim argues with Pres and socks him. Jim leaves with Dark Hazard and hitchhikes. They travel to Australia. Jim wins money, and Valerie bosses him.
This drama is fairly realistic in the human conflict the gambling causes; but few gamblers are as lucky as Jim.